The current-spreading effect of an LED element regards the brightness thereof. Conventionally, an electrode pad can be formed on the top semiconductor layer to input current to an LED element, and one or more than one extension electrodes extended from the electrode pad can be also formed on the top semiconductor layer to improve current-spreading.
Nevertheless, the disposition of the extension electrodes causes adverse influence on light-extraction of the LED element because the extension electrodes are metal so as to absorb or block the light of the LED element. Furthermore, if the contact area between the extension electrode and the top semiconductor layer is insufficient, the forward voltage of the LED element may be raised so the electrical efficiency is lowered accordingly.
In addition, the LED element can be further connected to other components in order to form a light emitting apparatus. The LED element may be mounted onto a submount with the side of the substrate of the LED element, or a solder bump or a glue material may be formed between the submount and the light-emitting element, therefore a light-emitting apparatus is formed. Besides, the submount further comprises the circuit layout electrically connected to the electrode of the light-emitting element via an electrical conductive structure such as a metal wire.